The present invention relates in general to semiconductor devices, and more particularly to integrated image capturing circuits fabricated on semiconductor substrates.
Most integrated imaging circuits are formed to include arrays of photoactive pixel circuits suitable for capturing images projected on the arrays. The pixel circuits typically include photoactive or photoreceptive devices as well as control and selection transistors. Such integrated imaging circuits are used in copiers, scanners, digital cameras and other devices.
The quality of the captured images typically is determined by the fill factor of the arrays, i.e., the portion of the array which is occupied by the photoactive devices. An array with a high fill factor captures more of the light projected on the array and consequently produces a higher quality captured image.
Previous integrated imaging circuits suffer from a high cost due to the large die area occupied by the arrays of pixel circuits. However, if the area of each pixel circuit is decreased, the fill factor is reduced and the quality of the captured images is degraded.
Hence, there is a need for an imaging circuit which can be fabricated at a reduced cost while maintaining or improving the quality of captured images.